I have a Lumia 920. People complain about the stock FB app, but they just released a new Facebook Beta app that's pretty solid. The twitter app is nice too and if you're into Instagram a new pay app called itsdagram just came out that's so far is very good. An ad supported version is coming out soon.

Some apps that could really benefit from great live tiles have pretty bad live tiles, like ESPN Scorecenter for instance freezes on the live tile a lot. Overall though I'm very satisfied with it.